| The rapid developments of high-speed train industry promote the relevant materials and technology to create constant innovation.As an important safety component of high-speed train,the improvement of impact resistance is the focus of the research of high speed train's window glass.Many factors of glass surface,such as surface compressive stress,depth of compressive stress layer,center tension,surface micro-cracks,have an important impact on the impact resistance of glass.Chemical tempering,a well-known glass reinforced technology,can greatly improve the surface compressive stress of glass,however,high-speed train's window glass not only requires the surface compressive stress to be 900 MPa or more,but also requires the depth of compressive stress layer to be 50 ?m or more,the current chemical tempering process is unable to fulfill the requirements.On the other hand,the strengthening technology of glass surface coating,although a few works had been reported,is still lack of systematic research,especially lack of the systematic study of the influence of surface coating thickness on glass strength.This article,under the application background of high-speed train's window glass and around the topics of(1)new processing of chemical tempering and(2)systematic study of surface coating enhancement,carried out the following two aspects of the study.(1)The effects of molten salt additives on the surface compressive stress and the thickness of the stress layer were investigated by orthogonal experiment,using ordinary soda lime silicate glass as raw materials and using FSM-6000LE surface stress meter,EDS energy spectrum analysis and other test methods.As a result,the additive formulation was obtained.(2)The influence of film thickness and the coating of different impact surfaces on the bending strength of the glass was studied by using the micron-scale silica coating and sol spraying process.The main contents and conclusions of this paper are as follows:1.On the basis of traditional chemical tempering technology,the new molten salt additive formula was explored through a design of orthogonal test,and the stress intensity of the glass surface is effectively improved according to the results of bicyclic test.The results show that the new formula increases glass anti-bending strength by nearly 100 MPa when comparing to the old formula.2.The air gun spraying technology was used to spray silica sol on glass surface,and the micron-scale silica coating thickness was controlled by spraying processing.The interface adhesion between the film and glass,and the thickness uniformity of the coating were measured by SEM and optical interferometer,respectively.Results show that the micron-scale silica coating bonds with glass surface very closely without no voids and pores on the interface.The coating thickness deviation is small,showing the overall uniformity is good.3.The surface strength and bending strength of glass were enhanced by micron-scale silica coating and the effects of three kinds of film thickness on the bending strength of glass were compared.Results show that glass bending strength increases with the increase of the coating thickness.By changing the coating orientation of glass surface,it was found that the bending strength of glass with film backing to the impact is significantly greater than that with film facing up to the impact.The glass surface of backing to the impact becomes a fragile surface due to suffering a tensile stress when being impacted.The cracks caused by tensile stress on glass surface can be healed by the SiO2 coating,resulting the orientation effect of improving the bending strength. |
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